2022 day 2 (bash)

2022/day02/README.org

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+** --- Day 2: Rock Paper Scissors ---
+The Elves begin to set up camp on the beach. To decide whose tent gets
+to be closest to the snack storage, a giant
+[[https://en.wikipedia.org/wiki/Rock_paper_scissors][Rock Paper
+Scissors]] tournament is already in progress.
+
+Rock Paper Scissors is a game between two players. Each game contains
+many rounds; in each round, the players each simultaneously choose one
+of Rock, Paper, or Scissors using a hand shape. Then, a winner for that
+round is selected: Rock defeats Scissors, Scissors defeats Paper, and
+Paper defeats Rock. If both players choose the same shape, the round
+instead ends in a draw.
+
+Appreciative of your help yesterday, one Elf gives you an /encrypted
+strategy guide/ (your puzzle input) that they say will be sure to help
+you win. "The first column is what your opponent is going to play: =A=
+for Rock, =B= for Paper, and =C= for Scissors. The second column--"
+Suddenly, the Elf is called away to help with someone's tent.
+
+The second column, you reason, must be what you should play in response:
+=X= for Rock, =Y= for Paper, and =Z= for Scissors. Winning every time
+would be suspicious, so the responses must have been carefully chosen.
+
+The winner of the whole tournament is the player with the highest score.
+Your /total score/ is the sum of your scores for each round. The score
+for a single round is the score for the /shape you selected/ (1 for
+Rock, 2 for Paper, and 3 for Scissors) plus the score for the /outcome
+of the round/ (0 if you lost, 3 if the round was a draw, and 6 if you
+won).
+
+Since you can't be sure if the Elf is trying to help you or trick you,
+you should calculate the score you would get if you were to follow the
+strategy guide.
+
+For example, suppose you were given the following strategy guide:
+
+#+begin_example
+A Y
+B X
+C Z
+#+end_example
+
+This strategy guide predicts and recommends the following:
+
+- In the first round, your opponent will choose Rock (=A=), and you
+  should choose Paper (=Y=). This ends in a win for you with a score of
+  /8/ (2 because you chose Paper + 6 because you won).
+- In the second round, your opponent will choose Paper (=B=), and you
+  should choose Rock (=X=). This ends in a loss for you with a score of
+  /1/ (1 + 0).
+- The third round is a draw with both players choosing Scissors, giving
+  you a score of 3 + 3 = /6/.
+
+In this example, if you were to follow the strategy guide, you would get
+a total score of =15= (8 + 1 + 6).
+
+/What would your total score be if everything goes exactly according to
+your strategy guide?/
+
+Your puzzle answer was =11841=.
+
+** --- Part Two ---
+The Elf finishes helping with the tent and sneaks back over to you.
+"Anyway, the second column says how the round needs to end: =X= means
+you need to lose, =Y= means you need to end the round in a draw, and =Z=
+means you need to win. Good luck!"
+
+The total score is still calculated in the same way, but now you need to
+figure out what shape to choose so the round ends as indicated. The
+example above now goes like this:
+
+- In the first round, your opponent will choose Rock (=A=), and you need
+  the round to end in a draw (=Y=), so you also choose Rock. This gives
+  you a score of 1 + 3 = /4/.
+- In the second round, your opponent will choose Paper (=B=), and you
+  choose Rock so you lose (=X=) with a score of 1 + 0 = /1/.
+- In the third round, you will defeat your opponent's Scissors with Rock
+  for a score of 1 + 6 = /7/.
+
+Now that you're correctly decrypting the ultra top secret strategy
+guide, you would get a total score of =12=.
+
+Following the Elf's instructions for the second column, /what would your
+total score be if everything goes exactly according to your strategy
+guide?/
+
+Your puzzle answer was =13022=.
+
+Both parts of this puzzle are complete! They provide two gold stars: **